﻿using System;   
using System.Collections.Generic;   
using System.Data;   
using System.IO;   
using System.Text;   
using System.Web; 
using NPOI;

using NPOI.HPSF;
using NPOI.HSSF;
using NPOI.HSSF.UserModel;
using NPOI.HSSF.Util;
using NPOI.POIFS;
using NPOI.Util;
using System.Collections;


public class ExcelHelper
{
    /// <summary>   
    /// DataTable导出到Excel文件   
    /// </summary>   
    /// <param name="dtSource">源DataTable</param>   
    /// <param name="strHeaderText">表头文本</param>   
    /// <param name="strFileName">保存位置</param>   
    /// <Author>柳永法 http://www.yongfa365.com/ 2010-5-8 22:21:41</Author>   
    //public static void Export(DataTable dtSource, string strHeaderText, string strFileName)
    //{
    //    using (MemoryStream ms = Export(dtSource, strHeaderText))
    //    {
    //        using (FileStream fs = new FileStream(strFileName, FileMode.Create, FileAccess.Write))
    //        {
    //            byte[] data = ms.ToArray();
    //            fs.Write(data, 0, data.Length);
    //            fs.Flush();
                
    //        }
    //    }
    //}

    /// <summary>   
    /// DataTable导出到Excel的MemoryStream   
    /// </summary>   
    /// <param name="dtSource">源DataTable</param>   
    /// <param name="strHeaderText">表头文本</param>   
    /// <Author>柳永法 http://www.yongfa365.com/ 2010-5-8 22:21:41</Author>   
    public static MemoryStream Export(DataTable dtSource, string strHeaderText, string strFileDate)
    {
        NPOI.HSSF.UserModel.HSSFWorkbook workbook = new NPOI.HSSF.UserModel.HSSFWorkbook();
        NPOI.HSSF.UserModel.HSSFSheet sheet = workbook.CreateSheet();
  

        HSSFCellStyle dateStyle = workbook.CreateCellStyle();
        HSSFDataFormat format = workbook.CreateDataFormat();
        dateStyle.DataFormat = format.GetFormat("yyyy-mm-dd");

        //取得列宽   
        int[] arrColWidth = new int[dtSource.Columns.Count];
        foreach (DataColumn item in dtSource.Columns)
        {
            arrColWidth[item.Ordinal] = Encoding.GetEncoding(936).GetBytes(item.ColumnName.ToString()).Length;
        }
        for (int i = 0; i < dtSource.Rows.Count; i++)
        {
            for (int j = 0; j < dtSource.Columns.Count; j++)
            {
                int intTemp = Encoding.GetEncoding(936).GetBytes(dtSource.Rows[i][j].ToString()).Length;
                if (intTemp > arrColWidth[j])
                {
                    arrColWidth[j] = intTemp;
                }
            }
        }



        int rowIndex = 0;

        foreach (DataRow row in dtSource.Rows)
        {
            #region 新建表，填充表头，填充列头，样式
            if (rowIndex == 65535 || rowIndex == 0)
            {
                if (rowIndex != 0)
                {
                    sheet = workbook.CreateSheet();
                }

                #region 表头及样式
                {
                    HSSFRow headerRow = sheet.CreateRow(0);
                    headerRow.HeightInPoints = 25;
                    headerRow.CreateCell(0).SetCellValue(strHeaderText);

                    HSSFCellStyle headStyle = workbook.CreateCellStyle();
                    headStyle.Alignment = CellHorizontalAlignment.CENTER;
                    HSSFFont font = workbook.CreateFont();
                    font.FontHeightInPoints = 20;
                    font.Boldweight = 700;
                    headStyle.SetFont(font);

                    headerRow.GetCell(0).CellStyle = headStyle;

                    sheet.AddMergedRegion(new Region(0, 0, 0, dtSource.Columns.Count - 1));
                    headerRow.Dispose();
                }
                #endregion

                #region 填充报表时间
                {
                    HSSFRow headerRow = sheet.CreateRow(1);
                     
                    headerRow.CreateCell(0).SetCellValue(strFileDate);

                    HSSFCellStyle headStyle = workbook.CreateCellStyle();
                    headStyle.Alignment = CellHorizontalAlignment.RIGHT;
                    HSSFFont font = workbook.CreateFont();
                    
                    headStyle.SetFont(font);

                    headerRow.GetCell(0).CellStyle = headStyle;
                    sheet.AddMergedRegion(new Region(1, 0, 1, dtSource.Columns.Count - 1));
                    headerRow.Dispose();
                }
                #endregion


                #region 列头及样式
                {
                    HSSFRow headerRow = sheet.CreateRow(2);


                    HSSFCellStyle headStyle = workbook.CreateCellStyle();
                    headStyle.Alignment = CellHorizontalAlignment.CENTER;

                    HSSFFont font = workbook.CreateFont();
                    font.FontHeightInPoints = 18;
                    font.FontHeightInPoints = 15;
 
                    headStyle.SetFont(font);


                    foreach (DataColumn column in dtSource.Columns)
                    {
                        headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
                        headerRow.GetCell(column.Ordinal).CellStyle = headStyle;

                        //设置列宽   
                        sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + 1) * 256);

                    }
                    headerRow.Dispose();
                }
                #endregion

                rowIndex = 3;
            }
            #endregion

            #region 填充内容
            HSSFRow dataRow = sheet.CreateRow(rowIndex);
            {
                HSSFCellStyle headStyle = workbook.CreateCellStyle();
                headStyle.Alignment = CellHorizontalAlignment.CENTER;

                HSSFFont font = workbook.CreateFont();
                font.FontHeightInPoints = 19;
                font.FontHeightInPoints = 10;
 
                headStyle.SetFont(font);
            }
            foreach (DataColumn column in dtSource.Columns)
            {

                HSSFCell newCell = dataRow.CreateCell(column.Ordinal);

                string drValue = row[column].ToString();

                switch (column.DataType.ToString())
                {
                    case "System.String"://字符串类型   
                        newCell.SetCellValue(drValue);
                        break;
                    case "System.DateTime"://日期类型   
                        DateTime dateV;
                        DateTime.TryParse(drValue, out dateV);
                        newCell.SetCellValue(dateV);

                        newCell.CellStyle = dateStyle;//格式化显示   
                        break;
                    case "System.Boolean"://布尔型   
                        bool boolV = false;
                        bool.TryParse(drValue, out boolV);
                        newCell.SetCellValue(boolV);
                        break;
                    case "System.Int16"://整型   
                    case "System.Int32":
                    case "System.Int64":
                    case "System.Byte":
                        int intV = 0;
                        int.TryParse(drValue, out intV);
                        newCell.SetCellValue(intV);
                        break;
                    case "System.Decimal"://浮点型   
                    case "System.Double":
                        double doubV = 0;
                        double.TryParse(drValue, out doubV);
                        newCell.SetCellValue(doubV);
                        break;
                    case "System.DBNull"://空值处理   
                        newCell.SetCellValue("");
                        break;
                    default:
                        newCell.SetCellValue("");
                        break;
                }

            }
            #endregion

            rowIndex++;
        }

        ArrayList alc = new ArrayList();
        ArrayList alm = new ArrayList();
        int f = 0;
        for (int i = 4; i < rowIndex; i++)
        {
            HSSFRow rd1 = sheet.GetRow(i-1);
            HSSFRow rd = sheet.GetRow(i);
            string fName = rd1.Cells[0].ToString();
            string fN = rd.Cells[0].ToString();
           
            if (rd.Cells[0].ToString() == fName)
            {
                f++; 
            }
            else
            {
                alc.Add(f);
                alm.Add(fName);
                f = 0;
               
            }
            


        }
        int mm = 3;
        for (int i = 0; i < alc.Count; i++)
        {
            
            sheet.AddMergedRegion(new Region(mm, 0,mm+ (int)alc[i], 0));
            sheet.AddMergedRegion(new Region(mm, 1, mm + (int)alc[i], 1));
            mm += (int)alc[i]+1;
        }

        alm = new ArrayList();
        alc = new ArrayList();
        for (int i = 4; i < rowIndex; i++)
        {
            HSSFRow rd1 = sheet.GetRow(i - 1);
            HSSFRow rd = sheet.GetRow(i);
            string fName = rd1.Cells[2].ToString();
            string fN = rd.Cells[2].ToString();

            if (rd.Cells[2].ToString() == fName)
            {
                f++;
            }
            else
            {
                alc.Add(f);
                alm.Add(fName);
                f = 0;

            }
        }
        mm = 3;
        
        for (int i = 0; i < alc.Count; i++)
        {

            sheet.AddMergedRegion(new Region(mm,2, mm + (int)alc[i], 2)); 
            mm += (int)alc[i] + 1;
        }
        using (MemoryStream ms = new MemoryStream())
        {
            workbook.Write(ms);
            ms.Flush();
            ms.Position = 0;

            sheet.Dispose();
            return ms;
        }

    }


    /// <summary>   
    /// 用于Web导出   
    /// </summary>   
    /// <param name="dtSource">源DataTable</param>   
    /// <param name="strHeaderText">表头文本</param>   
    /// <param name="strFileName">文件名</param>      
    public static void ExportByWeb(DataTable dtSource, string strHeaderText, string strFileName, string strFileDate)
    {

        HttpContext curContext = HttpContext.Current;

        // 设置编码和附件格式   
        curContext.Response.ContentType = "application/vnd.ms-excel";
        curContext.Response.ContentEncoding = Encoding.UTF8;
        curContext.Response.Charset = "";
        curContext.Response.AppendHeader("Content-Disposition",
            "attachment;filename=" +HttpUtility.UrlEncode(strFileDate+strFileName, Encoding.UTF8)+".xls");

        curContext.Response.BinaryWrite(Export(dtSource, strHeaderText, strFileDate).GetBuffer());
        curContext.Response.End();

    }


    /// <summary>读取excel   
    /// 默认第一行为标头   
    /// </summary>   
    /// <param name="strFileName">excel文档路径</param>   
    /// <returns></returns>   
    public static DataTable Import(string strFileName)
    {
        DataTable dt = new DataTable();

        HSSFWorkbook hssfworkbook;
        using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read))
        {
            hssfworkbook = new HSSFWorkbook(file);
        }
        HSSFSheet sheet = hssfworkbook.GetSheetAt(0);
        System.Collections.IEnumerator rows = sheet.GetRowEnumerator();

        HSSFRow headerRow = sheet.GetRow(0);
        int cellCount = headerRow.LastCellNum;

        for (int j = 0; j < cellCount; j++)
        {
            HSSFCell cell = headerRow.GetCell(j);
            
        }

        for (int i = (sheet.FirstRowNum + 1); i <= sheet.LastRowNum; i++)
        {
            HSSFRow row = sheet.GetRow(i);
            
            for (int j = row.FirstCellNum; j < cellCount; j++)
            {
                if (row.GetCell(j) != null)
                { 
                    
                }
            } 
        }
        return dt;
    }
}